Does THC have a role in the management of dementia?

THC has been proposed as a potentially useful compound in the management of dementia, particularly for behavioral symptoms like aggression, agitation, trouble sleeping, wandering, and poor dietary intake. Further, some research in rodents has found that activation of cannabinoid receptor 2 (CB2) receptors in immune cells in the brain may reduce neuroinflammation, oxidative stress, and the formation of the amyloid plaques characteristic of Alzheimer’s disease.^[1]

A handful of randomized controlled trials, uncontrolled trials, and case reports have suggested that THC and its analogs might improve some of the behavioral and psychological symptoms of dementia, most notably aggression and agitation. THC was usually provided at low dosages (≤5 mg daily) and was reportedly well-tolerated, aside from sedation.^[1][2]

However, all studies have been small and short in duration, and the safety of THC (including its effect on cognitive function) has not been adequately explored in this population. Research is fairly consistent in showing that even a single dose of THC can cause short-term impairments in working memory and executive function in an otherwise healthy person, which raises the concern of how it might affect cognition in an older adult with dementia.^[3]

Overall, the current evidence of benefit is weak, and, paired with the known negative effects of THC on cognition, using THC in this context seems ill-advised at this time.